Artificial Reef & Coral
Restoration
Cambodian Reefs
Cambodia has an extensive coastline home to shallow water fringing reefs. Although the waters are more turbid than their Asian counterparts, the underwater world is bustling with life. The outer island reefs are particularly incredible with mesmerising expanses of coral and never-ending volcanic shaped fields of Diploastrea heliopora, anyone who has been diving with me knows my love for this stunning massive coral species!
The reefs around the Koh Rong Archipelago located within the Sihanoukville province are of important biological significance and support over 3000 people from five fishing communities. As most individuals in the region rely on fishing as their only source of income it is vital that we work in tandem to support their livelihoods whilst protecting the underwater world.
Unfortunately coral reef ecosystems have suffered an unprecedented loss of habitat-forming hard corals globally due to anthropogenic stressors and intensification of climate change in recent years. As recurrent events such as coral bleaching have increased, natural recovery rates of coral ecosystems have slowed. It is therefore important that we use techniques to aid coral recuperation and regeneration to reduce ecosystem decline and conserve what we have.
The loss of coral is evident on Cambodian reefs, particularly within the Koh Rong Archipelago, which is also subject to extensive fishing, coastal sedimentation and pollution. Research shows that the reefs were subject to three known mass bleaching events between 1998 and 2016 in which over 70% of corals were moderately to severely bleached. Another bleaching event was observed in 2019, however, there is no concrete data on this. It is therefore important that we use techniques to aid coral recuperation and regeneration to reduce further ecosystem decline in degraded areas by increasing the reefs natural resilience to climate change.
Through passive and active restoration we can provide sustainable and long-term solutions to regenerate areas of the reef that have been degraded, damaged or destroyed. A nursery allows the supply of coral fragments, by carefully choosing species of wild populations. This technique does not cause any major loss to the wild colonies on the reef, provided that a maximum of 10 % is taken from any one colony. Once these small fragments have been in the nursery for between 6 – 12 months, they will be large and robust enough to be planted back on to the reef. This in turn will create more habitats for marine organisms and increase the complexity and biodiversity of the reef. An artificial reef can provide refugia for fish species whilst extending the natural reef and increasing coral reef diversity.
PROJECT AIMS
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Use polycultures instead of monocultures to enhance coral growth and mass within nursery setting (as novel research from Clements & Hay, 2019 suggest).
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Propagate naturally occurring heat tolerant corals from neighbouring reefs to increase chance of survival against future climatic changes.
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Identify optimum conditions for maximising growth rates of various coral genotypes.
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Increase habitat complexity and biodiversity of degraded areas by transplanting nursery grown corals back onto the reef.
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Increase natural coral recruitment.
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Increase abundance, biomass and diversity of fish and invertebrate species.
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Conservation Education tool (for staff, guests and local communities).
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Extend the natural reef using artificial structures.
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Use airborne drones to identify and measure the small-scale three-dimensional features of a shallow-water reef before and after an artificial reef installation (Bennett, Younes & Joyce, 2020)
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Identify success rates of passive and active restoration on a Cambodian Reef System
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